如果三角形的底邊長(-3a+2b),高為(6a²-3ab+2b²),則面積＝
面積
=(-3a+2b)×(6a²-3ab+2b²)÷2
=(-3a+2b)×(6a²-3ab+2b²)×1/2
=[-3a×(6a²-3ab+2b²)+2b×(6a²-3ab+2b²)]×1/2
=[(-18a³+9a²b-6ab²)+(12a²b-6ab²+4b³)]×1/2
=(-18a³+4b³+21a²b-12ab²)×1/2
=-9a³+2b³+10.5a²b-6ab²